Specify a default module for TARGET_RECOVERY_UI_LIB.

This aligns the logic between {default,wear,vr}_device.cpp. They all
implement their default make_device() functions, but using different
RecoveryUI variants.

This CL creates a new module librecovery_ui_default that uses
ScreenRecoveryUI, which serves as the default value for
TARGET_RECOVERY_UI_LIB.

Test: lunch aosp_{angler,marlin,dragon,walleye}-userdebug;
      `mmma -j bootable/recovery` respectively.
Change-Id: I6755b09d96e4809bb1c17142895fe1cad95e5a02
Merged-In: I6755b09d96e4809bb1c17142895fe1cad95e5a02